Some of the newer quinolone derivatives (e.g., ciprofloxacin, enoxacin, fleroxacin, ofloxacin, pefloxacin, and amifloxacin) can be administered intravenously. Parenteral quinolone therapy is indicated primarily for patients receiving intensive care or in the early postoperative phase, for perioperative prophylaxis, and for patients with disturbed absorption. With respect to pharmacokinetic parameters, there are no substantial differences between parenteral and oral preparations of the quinolones. The quinolones have a long elimination half-life, a high volume of distribution, low protein-binding capacity, renal as well as extrarenal elimination, and limited biotransformation. Thus far, the limited data concerning the clinical efficacy and safety of quinolones are available only for the parenteral forms of ciprofloxacin, pefloxacin, and ofloxacin. The data available indicate good to excellent clinical and antimicrobiologic responses in patients with complicated urinary tract infections; respiratory tract infections; intraabdominal, bone and joint, skin and soft tissue infections; and difficult-to-treat infections (e.g., septicemia, nosocomial pneumonia, and fever of unknown origin in neutropenic patients).